#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
int bin_search(int arr[], int left, int right, int key) {
	int mid = 0;
	while (left < right) {
		mid = (left + right) / 2;
			if (arr[mid] < key) {
				left = mid + 1;
		}
			else if (arr[mid] == key) {
				return mid;
			}
			else {
				right = mid - 1;
			}
	}
	return -1;

}
int main() {
	int arr[] = {1,2,4,5,8,9};
	int left = 0;
	int right = sizeof(arr) / sizeof(arr[0]) - 1;
	int ret = bin_search(arr, left, right, 8);
	printf("ret=%d\n", ret);

	return 0;
}